Hi all,
As some of you know and have helped with, I have been developing a model of Old Hickory lake for the last few years. The model includes a hydrodynamic model (water depth, current, dam discharge, water temperature, etc.), environmental model (weather, wind, moon phase, etc.), habitat model (habitat types, bottom substrate, lake sections, etc.). The lake model is then coupled with a fisheries model (species, seasonal requirements, TWRA catch statistics, etc.) to estimate the amount and location of suitable habitat. The main species are largemouth bass, smallmouth bass, white crappie, black crappie, bluegill, channel catfish, and striped bass.
Well, the predictions are starting to come out of the model. I have a version for Largemouth bass running and the crappie should be running soon. So I figured I would see if the modeled predictions are anything like what you all are seeing while fishing.
Based on the last ten years of data, the longterm coldest water temperatures are found on Feb 5 and 6. The lake and fish are in winter patterns for sure. By Feb 26, a solid 5 degree water temperature rise has occurred and the fish should be reacting and moving into their early spring coldwater patterns. By March 28, the lake has warmed enough to see bass begin prespawn patterns and the onset of the early spawning should be around May 6 with the lake averaging 64 degrees. Spawning should peak in late May or early June and be over by June 18.
Those are the average conditions but as you know it can be a warm or cold year compared to average. Right now the main channel of the lake is predicted to be around 38 (Army Corps reports 37 at Rockland). The large creeks should be colder and the shallows colder yet due to cold temps and snow melt.
I ran the predictions with the next 10-day weather forecast to see if the warm spell would have an effect. Here is the results:
1. We are still in a winter fish pattern and will be through next week. So focus on winter bass habitat and fishing patterns. Main lake is warmer than the creeks.
2. By next Wednesday (Feb 16) the whole lake should be about the same temperature.
3. By late next week, shallow protected coves with northeast orientations could see a 10 degree warm up. Look for places where the wind can not blow all the water out to mix with the main channel. Bad weather or rain could wipe this out.
4. Because the fish are still in winter pattern, if the warm up occurs, find the protected shallows nearest your best winter spots. This is only the first warming pattern of the year so it will take some time for many fish to react and move shallow.
5. the past 10 years of creel survey information by TWRA suggests that Area 2 (from the powerlines downstream of Spencer and Station Camp Creeks to just below Bledsoe Creek) has the highest catch rate of .78 bass/hour followed by Area 1 (dam to powerlines) with .64 bass/hr. This may be an result of the warm water from the Gallatin Stream Plant in Area 2.
6. The lower lake (Drake's creek especially) warms up faster and prespawn catch rates are much higher than in the rest of the lake (1.3 fish/ hr in Area 1 during prespawn compared to .88 fish/hr in Area 2). So if the warming trend holds for a few weeks expect Drake's creek fishing to pick up fast.
7. This is just for Largemouth bass. Smallmouth do something totally different as they spawn much earlier in the year.
8. I am really interested in the crappie models as they move earlier than Largemouth. I will report that as it get the results.
So, if you all see anything to support or refute these predictions, I would be glad to hear about it. Also, this is based on the 10-day weather forecast and we all know how much that can change. So if it is snowing late next week, don't blame me
Hope it helps,
Jim